Best Method recommended method with best effort-to-efficacy tradeoff 2-3 months
Refrigerated (Opened)
- Refrigerate after opening commercial jars say "refrigerate after opening" to keep flavor and texture stable
- Keep the lid sealed tightly between uses
- Always use a clean utensil introducing crumbs or other food shortens shelf life
- Discard if you notice separation, off smell, or discoloration
Alternative another good method that's just different 3-6 months
Cool Pantry (Unopened)
- Store unopened commercial jars in a cool, dry pantry high acidity and preservatives keep sealed mayo safe short-term (3-6 months per USDA)
- Keep away from heat and direct sunlight
- Move to the fridge as soon as you open it
- The fridge door works well for opened jars - it offers more temperature stability
Fun Facts
- Mayonnaise is an emulsion - tiny droplets of oil suspended in water and held together by lecithin from egg yolk, which is why disturbing that balance (like freezing) ruins it.
- Commercial mayo's acidity (from vinegar or lemon juice) is low enough to inhibit many bacteria, which is why it is often blamed for picnic food poisoning it did not actually cause.